It has always been desirable to print manufactured articles with designs, advertising copy, slogans, owner affiliations, and the like. In the case of articles difficult to print, printing has often been accomplished through the use of silk screening techniques, which entail forcing thickened inks through a patterned screen in contact with the surface to be printed. While the silk screen process commonly involves the use of mechanical or power-operated presses, it may also be performed manually as well, and in fact, manual printing is sometimes the only practical method for silk screening articles possessing three-dimensional surfaces.
While the silk screen process is simple in concept, it is not without certain inherent drawbacks. For example, while single-color printing is relatively easy to accomplish, that involving multi-color reproduction requires the use of successive screens, each being confined to the application of a single color. Since the multiple colors are normally associated in an integral design, accuracy of placement of the design components on the articles being printed, i.e., the color register, is quite important. Such placement is frequently difficult to achieve, however, particularly on articles with three-dimensional surfaces. Furthermore, the process is time-consuming when performed manually, and it requires a relatively high degree of skill on the part of the practitioner.
In recent years, sublimation printing techniques have increasingly been employed in the printing of articles that are difficult to print. The sublimation process involves the printing of a desired design on a paper backing sheet by conventional printing techniques employing sublimation inks for the purpose, and then transferring the designs under heat and pressure from the backing sheet to the article being printed. Although somewhat dull and off-colored when printed on the backing sheet, sublimation inks have been found to possess the ability to produce brilliant colors and clear designs on the articles being printed; consequently, the process is now frequently employed.
Despite such notable advantages, however, sublimation printing is relatively unsatisfactory for printing certain types of articles. In the case of those fabricated from foamed materials, for instance, sublimation dyes have an unfortunate tendency to penetrate into the cellular structure of the articles, from which location the colors migrate beyond the area intended for printing. In the case of single-color printing, ink migration results in fuzzy definition and causes unintended color dilution. In the case of multi-colored printing, undesirable mixing of colors also results. The phenomenon described is particularly evident with the passage of time.
Similarly, in the case of elastomers, such materials are commonly compounded to include various extending oils, processing aids and the like, all of which tend to act as a solvent for sublimation dyes. When the dyes are imprinted on the surface of these materials, therefore, they tend to become solvated, and in that condition to disperse into unintended areas with the disadvantages previously described.
In the case of beverage insulators, for example, i.e. polymeric foamed sleeves designed to fit over beverage holders such as drinking glasses for the purpose of maintaining the contents thereof thermally constant, it is often desirable to imprint the outer surface of the insulators with the names of the owner, sport teams, logos, and the like. If such imprinting is not visually crisp and sharply defined, however, it greatly detracts from the appearance of the imprinted insulators, and consequently, adversely affects their marketability.
In view of the preceding, therefore, it is a first aspect of this invention to provide an improved process for imprinting foamed and elastomeric articles.
A second aspect of this invention is to provide a process for transferring imprinting with good definition onto the surfaces of articles, particularly those having cellular or elastomeric structures.
Another aspect of this invention is to provide an improved method for imprinting cellular or elastomeric articles with sublimation dyes.
An additional aspect of this invention is to provide a system for preventing the penetration of sublimation dyes into the interior of cellular or elastomeric substrates.
A further aspect of this invention is to provide a system for coating the surfaces of cellular or elastomeric articles with a barrier structure that prevents the passage of sublimation dyes therethrough.
Yet an additional aspect of this invention is to provide two-component barrier structures that enhance the printing of substrates.
A still further aspect of this invention is to provide a two-step process for coating cellular and elastomeric articles in order to facilitate their printing while avoiding the penetration of sublimation dyes into the interior thereof.